Does Your LCD Play Catch-Up To Your Mouse?

Dishes of Ryan writes "I fell in love with the idea of an LCD monitor, so I ended up buying a nice, shiny Dell 2001FP. However, nowhere, and I mean *nowhere* did I read about LCDs having an input lag on them. For instance, if I scoot the mouse across the screen, there is a noticeable delay between when I move the mouse and when the cursor moves. To prove it to people, made a video showing exactly what I mean. You can almost forget being king of the hill on twitch FPS games like Unreal Tournament. Are there any other Slashdotters out there that are as annoyed as I am? What did you do?"

Comments

Need a different monitor

[AKAImBatman]

No offense, but you need to get another monitor. I notice no "lag" between my iBook and CRTs, nor do I notice any lag on my new 17" KDS for my desktop. Having developed a few video games and GUIs, I have a fairly well trained eye. I can see the problem in the video, but I see no such problem on my systems.

Conclusion? Dell buys parts from the lowest bidder. Ergo, they are the lowest quality. Therefore, you need a better monitor.

Sorry.

Re:Need a different monitor

[AKAImBatman]

I just thought of something you might want to try. LCDs are a bit different than CRTs in that they are completely digital. Since the monitor is digital, it sometimes requires calibration when used with an analog connector. Check your manufacturers specs for the EXACT resolution AND refresh rate that they recommend. The monitor will run in other modes, but it supposedly won't do them as well.

Once you've set your resolution and refresh rate, be sure to use the auto-adjust button if your monitor has it. When I first got mine, I thought the picture looked like crap. Then I found the auto-adjust. With a push of a button, I suddenly saw the crispest text I'd ever seen in my life. Quite an improvement over CRT displays. :-)

Re:Need a different monitor

[Waffle Iron]

One thing I noticed is that if you have a screen full of anti-aliased text, the auto adjust may not have enough edges to crunch on. I have a big bitmap of alternating black and white pixels that I put up to test the monitor's synch to the pixel clock.

If I autoadjust while showing normal windows, the bitmap will usually still have fuzzy areas when I pull it up. If I autoadjust while the bitmap is being displayed, the monitor is able to lock onto it perfectly. The text looks noticeably better with a perfect lock, especially when using sub-pixel sampling on the fonts, which needs pixel-perfect alignment to work properly.

I have a shortcut to this image on my systems because I have a KVM switch, so I need to autoadjust a lot. No two systems have the exact same video timings.

Re:Need a different monitor

[Minna Kirai]

I'll take a poor CRT over a good LCD anyday.

I'd take the good LCD, sell it, and buy 2 good CRTs, and a motorcycle.

Re:Need a different monitor

[Venotar]

Megane said:
> I'll bet the monitor in question is connected
> with a VGA plug

And Zorilla responded:
> That Dell monitor is probably a rebadged Samsung
> or LG.

Megane,

I have one of the Dell 2001FPs connected via a VGA cable (it's on a machine that doesn't get used for much gaming so it's connected to a slightly older video card) and I haven't notice a lag when moving the mouse (although I'm in front of my Hercules right now, so I can't actually test to see if the Dell shows the symptoms displayed in his video).

Zorilla,

You're partially correct. The Dell 2001FP contains a LG.Philips LM201U04 panel. The rest of the monitor is Dell designed; although not Dell built.

Re:Need a different monitor

[Kizzle]

THANK YOU. Awesome trick. I put up the images as you described them. These worked for me. I did notice my LCD acting really weird when these images were being displayed. I don't recommend keeping the image on the monitor for any longer than needed. http://www.hackermedia.net/downloads/lcd-cal

Um, no.

[autopr0n]

I've used lots of LCDs, including plenty of DELL LCDs. The LCDs we've used at work were faded, and the colors looked awful after a copule of years. but I've never never seen any kind of lag like this in any kind of monitor.

My guess is that there is something wrong with the video drivers, or the mouse drivers, or some other part of his computer that's causing these problems.

I can't see the vid because the file is apperantly slashdotted.

Re:Um, no.

[suckmysav]

"The guy needs to do some other tests - if he brings up a window and types, do the characters appear to be delayed too?"

Reminds me of a guy who bought his dot-matrix printer in for repair twice because it would not print the letter K. No amount of testing was enough to convince him that this was simply not possible. It turned out his keyboard had a faulty K key, and the K was not appearing on his screen either.

Re:Reader Reviews

[Jacer]

Never, under any circumstances base buying decisions off of reviews from Newegg. Half the reviewers state they're first time system builders with no real idea of what there doing. The other half try to sound like they know what they're talking about, but obviously have no clue, or are just flat out lieing. Then you have the problem that newegg removes the reviews that are less than pleasant. Your best bet is to read a site that focuses on reviews and sells no hardware. Maybe Slashdot could start a hardware review section and do some unbiased hard journalism!

video-card inputs

[cbr2702]

One monitor runs off of my video card's digital input, and the other monitor runs off of the card's analog input.

You might get even better results if you tried using the video card's outputs.

Site and Video Mirror

[cybermint]

Site Mirror: Click here.
Video Only: Click here.

Re:What is this, a newsgroup?!?!?

[scottking]

if i had to choose between /. and Dell for tech support, no contest, i'd be posting.

Re:post the image?

[Waffle Iron]

I don't have a site handy, but you can make your own with Windows paint.exe. Just create a black-and-white bitmap, and the color palette is replace with various bit patterns. Floodfill the whole image with the 50% black pattern.

You can probably do the same thing with Gimp, but it's not immediately obvious to me how to do it.

My god, man - do know what you're suggesting?

[Anonymous Coward]

Again, moderators, stop giving mod points to idiots!

Slashdot as we know it would cease to exist!

Slashdot - where else you can be utterly wrong and get hailed as informative and insightful? Yeah, yeah - I meant besides FOX news.

Re:Cursor "Submarining"

[timeOday]

This was a big problem with passive matrix screens.

No, read the article:

Note: This is different than an LCD's response time. Response time measures how quickly an LCD pixel can turn on and off. It's a measurement that is pretty much used to say how much "ghosting" you can expect.

He's talking about fast response time (no ghosting) but noticeable latency between when the signal goes into the monitor and when it starts to be displayed (so he thinks).

To which my question is this: if the monitor is running several frames behind the video card, where are those frames being stored? We're talking about many megabytes of image data here. A single 1600x1200x32bpp frame is over 7 megabytes. The monitor has no buffer that could do such a thing.

To me this points to a cause in the computer rather than the monitor, perhaps in the drivers as others suggested.

Re:Nah, need a different OS

[mkldev]

Or just nuke and reinstall your existing OS. There's no way that's normal behavior unless something is really wrong. Best guess... probably some freak effect of an interrupt either not consistently being delivered or being frequently blocked by something else... you know, like the vertical blanking interrupt running at a quarter speed or something.

That's my guess. A lot of things happen during the vertical blanking interval or on some other similar periodic interrupt. In most OSes, this includes screen updates and mouse pointer redraws. This could be anything from a buggy driver to an IRQ conflict, or possibly even a bad trace on the motherboard (though the latter isn't anywhere near as likely).

If an OS reinstall doesn't solve the problem, there's probably something weird going on in the BIOS settings and/or the motherboard itself. Pull the BIOS battery for an hour. Try again. If that doesn't work... is your clock running slowly, too? If so, buy a new computer. If not... buy a new computer. EIther way. :-p

<rant>And speaking of IRQ conflicts... why hasn't any motherboard manufacturer broken with tradition and actually added enough distinctly addressable interrupt lines? I mean, the Mac has supported 64+ interrupts on its interrupt controller since 1995. Does it really take a decade of engineering to figure out how to cascade two interrupt controllers and add a driver to support it? Sheesh!</rant>

Sigh. Another victim of a 2004 computer crammed into a 1981 architecture....

Re:Cursor "Submarining"

[tincho_uy]

Well, maybe he has, like, a reeeaally loooonng cable...

how to do it in GIMP

[Mr Z]

The following sequence seems to do the trick w/ GIMP 1.2.x:

• Create a new greyscale image that's the size of your screen
• Go to "Filters->Render->Patterns->Checkerboard. " Pick a checkerboard size of 1.

That should get you a checkerboard pattern on a 1-pixel increment. I haven't seen what this does for an LCD monitor's ability to fine tune an analog signal (since I don't own such a display), but I think it's the pattern you're using. It's the same fill pattern the old monochrome Macs used for their desktops. LOTS of edges to sync on, on every line! :-)

--Joe

To answer all your questions...

[Dishes of Ryan]

First of all, thank you, everybody, for taking a look at this. I received a characteristically Slashdotty wealth of "you're an idiot" replies, and a good number of "I didn't read the full article and/or watch the video so I'm jumping to conclusions" replies as well. =) Those of you that read the article and offered your genuine insight, thank you.

It's all fine, though. I'd like to answer a few randomly culled questions here, and also summarize what I've found based on all the feedback so other potential LCD owners can get a better feel for what they're up against.

1. It's not the mouse. If you look at the video (which many of you probably couldn't), you'll see that I have a dual-head setup that includes a CRT. It's lightning-quick responsive on the CRT.
2. As I mentioned in the full article, even when I use a single head setup with just the LCD, the same lag is present. And to those that guarantee switching to a single head CRT on the system will show the same lag. I've tried that in the past, and, again, the CRT is lightning-quick.
3. I'm running at the native resolution (1600x1200) with things like ClearType off, running over DVI. For that matter, if I do switch it to a non-native res, it still exhibits the same level of lagginess. Same goes with switching it to analog. Same lag.
4. I've used this LCD with many different computers (laptops, other desktop machines) and the problem replicates itself on every machine, regardless of OS or drivers.
5. I've seen the same lag on every LCD I've ever seen or used, although the problem is not as great as this one. Examples are my laptop, work computers, family computers, etc. If you think that you don't have a lag, you probably do (compare with a CRT), but you're probably blessed with one that is minimal enough to not be immediately perceptible. My laptop is much more useable for things like games because the lag isn't nearly as bad.
6. People that use this LCD for gaming that claim they have no problems, I'd suggest you try switching back to a CRT for a comparison. The "feel" will likely immediately clue you in to the difference.
7. It's not the driver, as guaranteed as you'd like to say it is. I've tried every driver on the planet. Also, see #4 above.
8. Others recognize this to be an issue as well, with their 2001FPs and others. Some of the comments say that they hate LCDs for this very reason. A good number of people who primarily game have returned their LCDs because it messes them up on games like CS or Unreal Tournament.
9. To those that think I should have taken this to a troubleshooting forum on Dell or elsewhere, there was apparently an issue posted about it on Dell's site. Someone's solution was to bring it down to a 1280x1024. See #3. Other than Dell's site, I was unable to find mention of it anywhere else, even though, yes, GIMF.

The overall summary, which you may or may not agree with is: Most LCDs are laggier than CRTs (I'd be jumped in an alley if I went as far as to say *all* LCDs are, but I try to avoid sweeping generalizations). Do your own tests, and come to your own conclusions. If you're a gamer, be careful. And lastly, my Dell 2001FP may in fact be one of the laggiest LCDs in existence, *or* I just received a defective unit.

Thanks again, everybody, for the replies. I hope this helps some people. I know that I at least saw one person in the comments that learned something new, although it was, in fact, for something unrelated to the immediate post. =)

No K

[mopslik]

It turned out his keyboard had a faulty K key, and the K was not appearing on his screen either.

And thus the GNOME project was born...